National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

79°F

26°C

Humidity 74%
Wind Speed S 6 mph
Barometer 29.97 in (1014.1 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index82°F (28°C)
Last update 27 Aug 3:56 am CDT
Extended Forecast for

Lockhart TX

Heat Advisory August 27, 04:13am until August 27, 07:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 27, 04:13am until August 27, 07:00pm

    NOW until 7:00pm Thu

    Heat Advisory

  • Today

    High: 103 °F

    Mostly Sunny
    then Chance
    T-storms

  • Tonight

    Tonight: A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, then becoming mostly cloudy toward daybreak, with a low around 76. South southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 30%.

    Low: 76 °F

    Chance
    T-storms then
    Slight Chance
    Showers

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny and hot, with a high near 100. Heat index values as high as 106. Calm wind becoming east around 5 mph in the afternoon.

    High: 100 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: A 10 percent chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.

    Low: 75 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 99. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 99 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 75. South wind 5 to 10 mph.

    Low: 75 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny and hot, with a high near 99. Calm wind becoming southeast around 5 mph in the morning.

    High: 99 °F

    Hot

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 74 °F

    Mostly Clear

Detailed Forecast

Today
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 103. Heat index values as high as 109. Southwest wind around 5 mph becoming calm in the afternoon.
Tonight
A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, then becoming mostly cloudy toward daybreak, with a low around 76. South southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 30%.
Friday
A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny and hot, with a high near 100. Heat index values as high as 106. Calm wind becoming east around 5 mph in the afternoon.
Friday Night
A 10 percent chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.
Saturday
Sunny and hot, with a high near 99. Calm wind becoming east southeast around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 75. South wind 5 to 10 mph.
Sunday
Sunny and hot, with a high near 99. Calm wind becoming southeast around 5 mph in the morning.
Sunday Night
Mostly clear, with a low around 74. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Monday
Mostly sunny and hot, with a high near 99. South wind 5 to 10 mph.
Monday Night
Mostly clear, with a low around 75.
Tuesday
Mostly sunny and hot, with a high near 100.
Tuesday Night
Mostly clear, with a low around 75.
Wednesday
Mostly sunny and hot, with a high near 99.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Lockhart TX
 29.88°N 97.68°W (Elev. 525 ft)
Last Update:
3:44 am CDT Aug 27, 2026
Forecast Valid:
4am CDT Aug 27, 2026-6pm CDT Sep 2, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation